Graft polymerization of allyl benzoate using poly(allyl benzoate-co-2,2′-azobis[N-(2-propenyl)-2-methylpropionamide]) as polymeric azo-initiator

Abstract

SUMMARY: 2,29-Azobis[N-(2-propenyl)-2-methylpropionamide] (APMPA), a diallyl azo-compound useful as an initiator at elevated temperatures, was copolymerized with allyl benzoate (ABz) at 60 8 C, providing poly(ABz-co-APMPA) which acts as a polymeric azo-initiator. The effectiveness of poly(ABz-co-APMPA) to give a novel graft copolymer was checked by polymerizing ABz at 120 8 C and, furthermore, by the polymerization of styrene accompanied by crosslinking through termination by bimolecular combination.

Kinetics of the polymerizable azo initiator 2,2′‐azobis[N‐(2‐propenyl)‐2‐methylpropionamide] and its application to graft copolymerization

“…It was expected that the produced polymer had not only crosslinking networks but also an azo group, which could act as initiator at high temperatures, as shown in Scheme . Because the half‐life of the azo group of APMPA was 10 h at 96°C,9 the Arrhenius constant and activation energy of azo group decomposition were 4.77 × 10 14 s −1 and 1.37 × 10 5 J/mol, respectively. Using the Arrhenius equation and applying a first‐order decomposition reaction of APMPA, we found the conversion of the azo group of APMPA to be almost 5% in 4 h at 80°C.…”

“…Moreover, this method allows for a large amount of graft polymer to be polymerized. 2,2′‐Azobis[ N ‐(2‐propenyl)‐2‐methylpropionamide] (APMPA) is one such polymerizable azo initiator,9–12 with two vinyl groups and an azo group. By reacting the vinyl groups of APMPA with a comonomer, one can obtain a crosslinked copolymer having azo groups.…”

“…The azo group of the produced crosslinked copolymer can concomitantly be used as an initiator for graft polymerization. The half‐life of the azo group of APMPA is 10 h at 96°C 9. Thus, when the vinyl group of APMPA reacts with radicals during copolymerization, the decomposition of azo groups is negligible at 60–80°C.…”

“…Thus, when the vinyl group of APMPA reacts with radicals during copolymerization, the decomposition of azo groups is negligible at 60–80°C. Because of the high thermal stability of the azo group, APMPA is capable of producing a variety of copolymers having azo groups for the production of functional polymers 9. Therefore, new grafted polymers that are not available through ordinary graft polymerization procedures can easily be produced with APMPA.…”

“…Some studies concerning the reactivity of the vinyl groups of APMPA with styrene (ST) and vinyl benzoate have been published 9–12. However, in these studies, the copolymerization of the vinyl groups of APMPA with other monomers and graft polymerization with the produced copolymer having azo groups were insufficient for industrial applications.…”